Method for production of electric signs and an electric sign

ABSTRACT

A method for producing, by a laser that scans the rear side of a transparent object, figures and text that are recessed in the transparent material and that as seen from the outside ( 5 ) appear as a raised relief ( 1 ) and for which the effect of depth (d, d′) depends on the amplitude of a signal superposed the input, frequency-controlled laser power by which the screen pattern is obtained. By an optimal fineness of scanning relative the material of the sign, the figures may obtain a very strong luminescence even at a very low input edge-illumination power. Furthermore, the invention relates to an edge-illuminated electric sign (L 1,  L 2 ) with a figure produced by the manufacturing method according to the invention. Furthermore, the invention relates to a mounting system in the form of two interacting moulding strips ( 3, 4 ) for mounting one or more electric signs (L 1,  L 2 ) manufactured according to the invention.

TECHNICAL FIELD

The present invention relates to a manufacturing method for productionof edge-illuminated signs with figures having a large relief effect anda strong luminescence. The invention also comprises an edge-illuminatedelectric sign having a figure that has been applied to the electric signby a manufacturing method according to the invention.

PRIOR ART

Many different embodiments of edge-illuminated signs exist where thedesired figure, that may be a text or an image or a combination of both,appears as a luminous figure. One often used embodiment is that theluminous figure appears on a totally transparent base, which gives theimpression that the figure is freely floating. There are severaldifferent ways of obtaining this effect, whereof some involves applyingof the figure by an ink printing method on the rear side of atransparent glass or plastic plate, or that the figure is engraved.Examples of such embodiments are disclosed in GB 2,139,796 and U.S. Pat.No. 5,842,297.

It is characterising for these known methods that the figure does notget a uniform luminescence. The figure appears by stronger luminescenceon the side from which the edge-illumination comes. Efforts have beenmade by different methods to eliminate this, amongst other ways by usingprismatic techniques. In that case, small prismatic recesses of veryprecise angles have been engraved into the transparent, edge-illuminatedplate. If the prismatic recesses have edge surfaces that are angled by90° in relation to the rear side of the transparent plate, the light canpass without resulting luminescence, while other angles, about 45°, willgive the strongest luminescent effect. When the edge-illumination is putout, incoming light through the glass-clear front surface willpractically not result in any kind of luminescence, why the figure willbe practically invisible. One example of this embodiment is disclosed inUS 2001/0049893.

A need also exists for a flexible and easy to use mounting system thatadmits use of one or more edge-illuminated signs and fast and simplerearrangement of signs.

BRIEF ACCOUNT OF THE INVENTION

It is an object of the present invention to eliminate or at leastminimize the above mentioned problems, which is achieved by controllinga laser beam by a master program that makes the laser beam scan a linepattern at the same time as the laser beam is modulated by a frequencythat controls the amplitude of the input power to the laser and therebycreates a screen pattern at the same time as an image program issuperposed the amplitude-controlled scanning frequency, so that theinput laser power with amplitude variations proportional to the desiredfigure will burn at different depths and thereby give a relief of thefigure.

By the method according to the invention, a screen pattern of varyingdepth can be obtained, whereby e.g. a figure with large relief effectcan be achieved. Thanks to the microscopic screen pattern, a figure orimage is obtained that is clearly visible to the eye even when theedge-illumination is put out and a light is coming in from the outside,through the front side. By the very strong luminescent effect that canbe obtained by the microscopic screen pattern, it is possible to obtaina strongly luminous figure even when the edge-illumination is relativelyweak. Thereby, the figure will have a clear and precise appearance evenat a very small input power to the edge-illumination and independent offrom which direction it comes. In certain cases, e.g. when operation isto take place from accumulators charged by solar arrays, this can be ofdecisive importance for a long time operation with strong luminescenceall the time between recharging, whereby the signs are suitable e.g. forinformative text or warning purposes at locations where the power supplyis limited.

Yet another purpose of the invention is to provide an edge-illuminatedelectric sign with figures having a large relief effect and a strongluminescence.

Yet another purpose of the invention is to provide a mounting systemthat allows a flexible positioning of an electric sign. It isfurthermore an object to provide a mounting system that allows simplemounting and demounting of an electric sign.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in greater detail withreference to the attached drawing figures, of which:

FIG. 1 shows in perspective a relief of a figure,

FIG. 2 shows in perspective the principle of a screen pattern,

FIG. 3 shows in cross-section the principle of a screen pattern,

FIG. 4 shows a background film/foil,

FIG. 5 a, 5 b show cross-sections of two moulding strips,

FIG. 5 c-e show different ways to interconnect the two profiles,

FIG. 6 a shows a couple of mounted electric signs,

FIG. 6 b shows in detail two electric signs that are to beinterconnected,

FIG. 7 shows in detail a section of two interconnected electric signs,

FIG. 8 shows an electric sign,

FIG. 9 a, 9 b show two stop washers, and

FIG. 9 c shows a mounted stop washer.

DETAILED DESCRIPTION OF THE INVENTION

At least one or some of the advantages mentioned above can be obtainedby providing a transparent material with a screen pattern by amanufacturing method according to the invention.

FIG. 1 shows in perspective a relief 1 of a figure in the form of anoval-shaped protuberance 1 having sloping sides, such as it is desiredto appear on the face side of the sign.

FIG. 2 shows in perspective the principle of a screen pattern 2, toobtain this figure, and FIG. 3 shows the principle for this screenpattern 2, in cross-section. Details A and B show the structure of thescreen pattern 2 in a planar surface and a sloping surface,respectively. The screen pattern appears as rectangular parallelepipeds,here as cubes, in juxtaposition to each other, but due to the nature ofthe laser beam, the vertical surfaces shown in the figure will besomewhat sloping, so that the upper surface of a “rectangularparallelepiped” will be somewhat smaller than its opposing lowerimaginary counterpart

The screen pattern 2 is made by controlling a laser beam by a masterprogram that allows the laser beam to scan a line pattern, in which thedistance a between the lines is at most 1 mm, preferably at most 0.5 mmand even more preferred at most 0.2 mm, and that modulates the laserbeam power by a frequency that in proportion to the line distance formsa screen pattern where the screen dots are almost as long as they arewide. If one or both of the screen pattern distance and the frequencythat modulates the laser beam power is changed, the screen pattern maybecome of different character, e.g. long and narrow or short and wide.By adding an image program and/or a text program, that superpose(s) thefrequency-controlled power modulation, a varying depth d, d′ can beobtained.

When the laser beam, as controlled by the master and image programs,scans the rear side of a transparent, light guiding material that isvaporized in proportion to the input amplitude- and frequency-controlledamount of laser energy, figures can be made having the shape of imagesand text. These figures, in the form of a relief recessed in thetransparent material, appear as protruding a relief 1, when thetransparent material is viewed from the front side. The effect of depthof the relief 1 depends on the amplitude of the input and superposedlaser power at the same time as the desired screen pattern is presentall the time. It is this screen pattern that exists on all parts of theformed figure that gives the figure its strong luminescence whenedge-illuminated. By adapting the fineness of scanning (the size of thescreen pattern) to the material of the sign, the figures may obtain avery strong luminescence even at a very low input edge-illuminationpower.

An image program that is to superpose the frequency-controlled powermodulation, is fed into the laser control unit. The master programallows the laser beam to scan a line pattern at the same time as itgives the required screen pattern. A program written for a desiredfigure that can consist of text, images, patterns or the like, is fedinto the laser control unit and superposes the laser amplitude control,i.e. the input power, whereby the laser vaporizes the transparentmaterial of the sign down to different depths d, d′, see FIG. 3.

By frequency modulation of the input power to the laser, the screenpattern is made for which the fineness of scanning depends on thefrequency of the modulation and the scanning velocity of the laser overthe transparent material. In this way, the optimal fineness of scanningthat results in the best luminescence can be achieved independent of thedepth of the laser beam penetration into the material.

By modulating the laser beam power, a varying depth can be obtained,whereby a figure can be obtained e.g., which figure can be an image withstrong relief effect. Thanks to the very fine screen pattern, a figureor image is obtained that is clearly visible to the eye even when theedge-illumination is put out and a light is coming in from the outside,through the front side. By the very strong luminescence effect obtainedthanks to the screen pattern, a strongly luminous figure is obtainedeven when the edge-illumination is fairly weak, whereby the figure has aclear and precise appearance even at very low power input to theedge-illumination and independent of the direction from which it comes.In certain cases, e.g. when operation is to take place from accumulatorscharged by solar arrays, this can be of decisive importance for a longtime operation with strong luminescence all the time between recharging,whereby the signs are suitable e.g. for informative text or warningpurposes at locations where power supply from the power mains isimpossible.

The invention also comprises an edge-illuminated electric sign with afigure that has been applied to the rear side of the transparent, lightguiding material by aid of a modulated laser beam by the manufacturingmethod according to the invention. In addition to the above mentionedadvantages concerning the stronger and more uniform luminescence of thefigure applied onto the transparent material, it has also provenpossible to obtain an electric sign having a coloured rear side, alsohaving these features.

FIG. 4 shows the principle of the screen pattern 2 applied onto abackground film/foil, by which the above mentioned advantages can beobtained. By applying a film or a foil of desired colour onto the rearside of the electric sign, an electric sign can be obtained in which thefigure (not shown) appears against a coloured background. A screenpattern 2, in the form of a fine mesh net, has been produced on thisfilm or foil, by the manufacturing method according to the invention,where the screen pattern has a fineness that is proportional to theluminescence desired in different positions of the background. In thecase that a uniform luminescence is desired over the entire surface, thescreen pattern is given a fineness that is reciprocally proportional tothe distance from the illuminated edge. By removing, by aid of the laserbeam, a larger proportion of the material close to the illuminated edgethan at a distance from this illuminated edge, the contact surface sbetween the background film/foil and the transparent material, seedetail C, will be smaller close to the illuminated edge than at adistance there from. A smaller contact surface s will result in a weakerluminescence than a larger one. Furthermore, the same principle can beused in order to increase the luminescence of dark background coloursrelative to bright ones, which may be useful if a multicolouredbackground film/foil is used.

In addition to this, a preferred embodiment of the invention comprises amounting system for flexible mounting of the edge-illuminated electricsigns. The mounting system, the advantages of which are apparent fromthe description in connection with the different FIGS., comprises a pairof interacting moulding strips 3, 4, shown in cross-section in FIG. 5 aand 5 b. It is realised that the mounting system as such can be usedalso for positioning of other objects than electric signs, e.g. to mountother types of signs (e.g. conventional signs without need of powersupply) but also for flexible mounting of completely different kinds ofobjects, especially in combination with the ingenious principle also toenable power supply, it being realised that objects completely differentfrom light-emitting objects advantageously can be supplied withpower/mounted according to this principle. In a preferred embodiment,the moulding strips are manufactured from extruded aluminium. Othersuitable materials, such as plastics, are of course also encompassed bythe inventive concept.

A cross-section of one 3 of the moulding strips, hereinafter denotedmounting strip, is shown in FIG. 5 a. The mounting strip 3, that may beof considerable length, sometimes several metres, is intended to beattached in a suitable manner at a location where it is desired toposition one or more signs. The mounting strip can be positioned on awall, horizontally or vertically or at any chosen angle there between.The mounting strip 3 can furthermore be positioned to hang from aroof/ceiling or lie on the floor, as is desired.

The mounting strip 3 comprises an outside 5 and an inside 6. The profileis designed such that a longitudinal groove 7 is centrally placed on theoutside 5. The contours of the groove 7 can be resembled by the contoursof a diamond. On the inside 6 of the mounting strip 6, on either side ofthe groove 7, two passages 8 are arranged that run in parallel with thegroove 7 and that are arranged to hold an electric conduit. At the endof the mounting strip 3, these passages 8 also constitute a screwattachment for a stop washer that is described in greater detail inconnection with FIGS. 9 a and 9 b.

FIG. 5 b shows a cross-section of the second moulding strip 4,hereinafter denoted sign strip, in which the transparent, light-guidingmaterial that constitutes the electric sign, is to be attached. Thelength of this moulding strip corresponds essentially to the width ofthe electric sign to be displayed. The moulding strip is U-shaped and inthis embodiment it comprises three uniform protrusions 9, so calleddovetails, that are symmetrically positioned at a reciprocal angle of90° on the outside of the moulding strip. These protrusions 9 have ashaped adapted to the centre groove 7 on the outside 5 of the mountingstrip. Depending on which of the three protrusions 9 that is insertedinto the groove 7, the electric sign will be positioned in threedifferent directions, as is seen in FIGS. 5 c-e. Suitably, the signstrip 4 is provided with ribs 10A or some other kind of structure alongthe inside of the two walls 10 of the U, in order to increase theadhesion when the transparent, light guiding material is attached to thesign strip 4, by glue or silicon e.g. It is of course also possible toattach the transparent material in some other way, such as by screwunion or form fit.

The bottom of the U has an inside rounded shape, which circumferentiallyforms at least a semi-circle, preferably about ¾ of a circle, in orderto form a space 11 having a shape adapted to an electrical socket12,.that is inserted axially at the end of the sign strip 4.

FIG. 6 a shows a couple of examples of electric signs L1, L2 accordingto the invention, that have been mounted in a mounting system accordingto the invention. Besides enabling a very flexible mounting, themounting system is designed to enable very easy interconnection of andpower supply to a plurality of signs. Thanks to the mounting system, itis possible to rearrange signs quite easily, i.e. to switch signs orarrange them differently.

FIG. 6 b shows in perspective a portion of two electric signs L1, L2,that are to be interconnected in the same mounting strip 3. A connectingplug 13 is inserted in the socket 12 situated at the end of one L2 ofthe electric signs, to electrically interconnect the two electric signs.When the electric signs are brought together, the connecting plug 13will be inserted in the socket 12.

FIG. 7 shows an axial cross-section of the joint between twoelectrically interconnected electric signs L1, L2, their sockets 12 andthe connecting plug 13. The sockets 12 and the connecting plug 13 areschematically shown and it should be understood that the invention isnot limited to the type of connecting means that is used, but that allconnecting means on the market can be used, that enable the electricsigns to be interconnected in any order and in different directionsrelative each other.

FIG. 8 shows a longitudinal cross-section of an electric sign L. Thetransparent material is attached in the U-shaped sign strip 4.Light-emitting elements 14, here in the form of light-emitting diodes,are positioned in connection with the side surface 22 of the transparentmaterial, that is situated inside the sign strip 4. In this embodiment,the light-emitting elements 14 are placed in holes in the side surface22, but it is also conceivable to arranged a groove in the side surface.In another conceivable embodiment, the light-emitting element(s) 14is/are placed in connection with the side surface without being recessedin the same. Also, the Figure schematically shows the electricalinterconnection of the light-emitting elements 14 and the sockets 12that are positioned at the ends of the electric sign 4.

In order to close the electric circuit and to keep one or more lightsigns in place in the mounting strip 3, the mounting system comprises apair of stop washers 16, 17, shown in FIGS. 9 a and 9 b. A stop washeris mounted at the end of a mounting strip 3, by being screwed to it,which is shown in FIG. 9 c. For this purpose, the stop washer 16, 17 isprovided with two holes 18 that fit with the two passages 8 on theinside 6 of the mounting strip 3, which passages in this case constitutescrew attachments.

The stop washer 16 shown in FIG. 9 a and 9 c, comprises electricalconnectors in the form of a second connecting plug 19 that is arrangedon the stop washer 16 in connection with a hole 20. The electrical wires21 are led from the second connecting plug 19, along the outside of thestop washer or in a groove in the same. If desirable, they can be led onover the edge of the base part of the stop washer in order to be led toan adapter or some other power source, while being hidden and protectedfrom damage from the outside. Suitably, the electrical cables 21 areplaced in the passages 8 intended therefore, at the rear side of themounting strip 3.

The invention is not limited to that described above. It is realisedthat the mounting strip 3 and the sign strip 4 described above, only arepart of a preferred embodiment and that the skilled person can findobvious ways to use some other design to fulfil the same objects, theskilled person being familiar with that which is known per se concerningsimilar mounting arrangements and the principle here described.Furthermore, the mounting strip 3 may for example be wider and bedesigned with several grooves abreast, and be designed to have asemi-circular shape with grooves resulting in that signs mounted thereinpoint in different radial directions.

Furthermore, the sign strip 4 can be provided with more or fewerconnecting means 9 (dovetails), in order to allow the electric signs L1,L2 to be directed in other directions than that shown in the Figures. Itis also realised that a connecting means 9 having an outer circularshape, can enable infinitely variable positioning of the sign, byinteraction with a groove 7 adapted therefore in the mountingarrangement 3, which groove will give a desired friction/clamp fit.

It is furthermore realised that the invention not is limited to the useof two interacting strips, but that the electric sign can be mounted byany other mounting arrangement. For example, a mounting arrangement thatis arranged along a shorter portion of the edge-illuminated side beused, e.g. at the middle or at the respective end parts of theedge-illuminated side. This mounting arrangement would preferably alsocomprise electrical connectors and one or more light-emitting elements,but these can also be mounted in the electric sign in some other way. Inthe case that two interacting mounting devices are used, it should berealised that the mounting arrangements that are fixedly mounted in theplace where it is desired to position one or more electric signs.

It should also be realised that an electric sign can be either shorteror longer, and that it may comprise more or fewer light-emittingelements 14, than that shown above. Other types of light-emittingelements can be used than light-emitting diodes. Electric signs ofdiffering sizes can be combined in one and the same mounting system.

1-15. (canceled)
 16. A manufacturing method for production of anedge-illuminated sign with one or more figures having a large reliefeffect and a strong luminescence, the method comprising controlling alaser beam using a master program that makes the laser beam scan a linepattern at the same time as the laser beam is modulated by a frequencythat controls the amplitude of the input power to the laser and therebycreates a screen pattern at the same time as an image program issuperposed the amplitude-controlled scanning frequency, so that theinput laser power with amplitude variations proportional to the desiredfigure will burn at different depths and thereby give a relief of thefigure, in the sign.
 17. A manufacturing method according to claim 16,wherein lines of the line pattern have a distance from each other thatis essentially equal to the length of the screen pattern.
 18. Amanufacturing method according to claim 17, wherein lines of the linepattern have a distance from each other that is essentially equal toabout 0.1 mm.
 19. A manufacturing method according to claim 16, whereinthe lines of the line pattern have a distance from each other that isdifferent from the length of the screen pattern.
 20. A manufacturingmethod according to claim 16, wherein the lines of the line pattern havea distance from each other that are larger or smaller than the length ofthe screen pattern obtained by the frequency that controls the amplitudeof the input laser power and thereby can create screen patterns ofdiffering character.
 21. An edge-illuminated electric sign comprising afigure that is luminous when illuminated, wherein the figure has beenapplied to the electric sign by a manufacturing method comprisingcontrolling a laser beam using a master program that makes the laserbeam scan a line pattern at the same time as the laser beam is modulatedby a frequency that controls the amplitude of the input power to thelaser and thereby creates a screen pattern at the same time as an imageprogram is superposed the amplitude-controlled scanning frequency, sothat the input laser power with amplitude variations proportional to thedesired figure will bum at different depths and thereby give a relief ofthe figure, in the sign.
 22. An edge-illuminated electric signcomprising a film or foil with a screen pattern, in which the screenpattern has a fineness proportional to the luminescence desired indifferent positions of the background and that the fineness is alsoproportional to the distance to the illuminated edge, the screen patternbeing produced by controlling a laser beam using a master program thatmakes the laser beam scan a line pattern at the same time as the laserbeam is modulated by a frequency that controls the amplitude of theinput power to the laser and thereby creates a screen pattern at thesame time as an image program is superposed the amplitude-controlledscanning frequency, so that the input laser power with amplitudevariations proportional to the desired figure will burn at differentdepths and thereby give a relief of the figure, in the sign.
 23. Anedge-illuminated electric sign according to claim 22, further comprisinga first mounting device, that is adapted to position and/or protectlight-emitting elements at or inside an edge portion of said electricsign
 24. An edge-illuminated electric sign according to claim 23,wherein said mounting device is a continuous element that is arrangedalong a main part of said edge portion.
 25. An edge-illuminated electricsign according to claim 23, wherein said mounting device is providedwith at least one connecting means, arranged to enable positioning ofthe electric sign at a desired location.
 26. An electric sign accordingto claim 25, wherein said connecting means is a male or female elementfor interaction with an erecting device having a therefore adapted maleor female element, for mounting of the electric sign.
 27. An electricsign according to claim 25, wherein said mounting device is providedwith at least two connecting means, arranged at different angles inrelation to each other.
 28. An electric sign according to claim 27,wherein said mounting device is provided with at least two connectingmeans displaced by 90°.
 29. An edge-illuminated electric sign accordingto claim 23, wherein said mounting device, at least at one of its endportions, is provided with a connector that is connected to saidlight-emitting elements.
 30. An edge-illuminated electric sign accordingto claim 29, wherein said mounting device is provided with connectors atboth ends.
 31. An edge-illuminated electric sign according to claim 29,wherein said erecting device has at least one connector for interactionwith said connector at said sign.
 32. An edge-illuminated electric signaccording to claim 23, wherein said mounting device is a profiledelement.
 33. An edge-illuminated electric sign according to claim 32,wherein said mounting device is an extruded profiled element.
 34. Anedge-illuminated electric sign according to claim 23, wherein saiderecting device is a profiled element.
 35. An edge-illuminated electricsign according to claim 34, wherein said erecting device is an extrudedprofiled element.